State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
Xin-Lin Gong
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
Guo-Cheng Li
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
Ling-Qiao Huang
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
Chao Ning
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
Feeding and oviposition deterrents help phytophagous insects to identify host plants. The taste organs of phytophagous insects contain bitter gustatory receptors (GRs). To explore their function, the GRs in Plutella xylostella were analyzed. Through RNA sequencing and qPCR, we detected abundant PxylGr34 transcripts in the larval head and adult antennae. Functional analyses using the Xenopus oocyte expression system and 24 diverse phytochemicals showed that PxylGr34 is tuned to the canonical plant hormones brassinolide (BL) and 24-epibrassinolide (EBL). Electrophysiological analyses revealed that the medial sensilla styloconica of 4th instar larvae are responsive to BL and EBL. Dual-choice bioassays demonstrated that BL inhibits larval feeding and female oviposition. Knock-down of PxylGr34 by RNAi attenuates the taste responses to BL, and abolishes BL-induced feeding inhibition. These results increase our understanding of how herbivorous insects detect compounds that deter feeding and oviposition, and may be useful for designing plant hormone-based pest management strategies.
